1. Field of the Invention
The invention relates to a method for detecting genetic variations in bovine which influence meat tenderness.
2. Description of the Prior Art
Variation in meat tenderness has significant impact on consumer satisfaction with beef, however, classical selection techniques have not been effective in eliminating animals yielding undesirable palatability traits. Establishing the genetic basis for variation in meat tenderness would likely aid in the development of selection criteria for improving meat tenderness in cattle.
Currently, there is only one commercially available genetic test for meat tenderness. This test, which is marketed from Australia, tests for variation in the bovine calpastatin (CAST) gene.
The CAPN1 gene encodes a cysteine protease, micromolar calcium activated neutral protease (also known as mu-calpain), that degrades myofibrillar proteins under post mortem conditions and appears to be the primary enzyme in the post mortem tenderization process (Koohmaraie, M. 1992. The role of Ca2+-dependent proteases (calpains) in postmortem proteolysis and meat tenderness. Biochemie 74:239–245; Koohmaraie, M. 1994. Muscle proteinases and meat aging. Meat Science 36:93–104; Koohmaraie, M. 1996. Biochemical factors regulating the toughening and tenderization process of meat. Meat Sci. 43:S193–S201). Regulation of mu-calpain activity has been correlated with variation in meat tenderness (Geesink, G. H., and M. Koohmaraie. 1999. Effect of calpastatin on degradation of myofibrillar proteins by mu-calpain under postmortem conditions. J. Anim. Sci. 77:2685–2692). Bovine CAPN1 has been mapped to the telomeric end of BTA29 (Smith T. P. L. et al. 2000a. Bovine CAPN1 maps to a region of BTA29 containing a quantitative trait locus for meat tenderness. J. Anim. Sci. 78:2589–2594) and recently a quantitative locus (QTL) for tenderness was found to be segregating in this region of BTA29 in two resource populations (Casas E. et al. 2000. Quantitative trait loci affecting growth and carcass composition of cattle segregating alternate forms of myostatin. J. Anim. Sci. 78:560–569; Morris C. A. et al., 2001. Progress in DNA marker studies of beef carcass composition and meat quality in New Zealand and Australia. Proc., Assn. Advance. Anim. Breed. Genet. 14:17–22). The moderate effect (0.4 standard deviation) of this QTL on Warner-Bratzler shear force, a mechanical measurement of tenderness (AMSA, 1995. Research guidelines for cookery, sensory evaluation and instrumental tenderness measurements of fresh meat. Am. Meat Sci. Assn., Chicago, Ill.) in the U.S. Meat Animal Research Center (MARC) population supported the evaluation of CAPN1 as a candidate gene for tenderness within this population.